DESCRIPTION: Between 800 and 1,200 thousand buildings in the United States are the worksites to millions of workers where indoor environmental problems have arisen. Building-related symptoms, illnesses, and health complaints result in significant economic losses due to absenteeism, in addition to the direct effect on workers' health. Although the specific agents associated with these effects are not known, many studies have demonstrated that these symptoms, illnesses and complaints are related to poor indoor air quality and perceived physical discomfort. Ventilation techniques for the entire room volume as mixing or displacement ventilation cannot provide the required specifications for individual control and the condition of a small volume around the occupant (the microclimate). Attempts are now being made to blend the macroclimate control with a user-controllable microclimate control zone. The objective of this proposed research is to evaluate the performance of a new ventilation concept which combines displacement ventilation with task ventilation; the so-called personal displacement ventilation system. Controlled environmental chamber tests as well as computational fluid dynamics (CFD) modeling will be used to evaluate the general performance of personal displacement ventilation against defined indoor air quality and thermal comfort criteria. Critical parameters of human exposure and thermal comfort will be investigated under conditions of a small office setting with different source configurations, ventilation design, and load conditions. CFD models will elucidate the interactions among these factors including simulated buoyancy sources. Reasonable recommendations for the use of personal displacement ventilation will be offered. An evaluation of the performance of a personal displacement ventilation system to provide the microclimate will provide guidance on further development/use. Results from this study could lead to improved ventilation system design that could even provide for individual control of indoor microclimates; such a system could also be used to protect susceptible and sensitive sub-populations in the areas such as patient waiting rooms, wards, schools with allergic children, homeless shelters, etc.